This invention relates to an improved fluid composition for use in metal cutting operations. More particularly the invention relates to fluid compositions comprising a hydrocarbon and an aluminum acid alkylorthophosphate for use as cutting fluids in metal-machining operations. Still more particularly, the invention relates to a method for reducing wear of tools used in metal-machining operations comprising the including of an aluminum acid alkylorthophosphate as an additive for hydrocarbon cutting fluids.
Finished metal parts are usually machined to final size and shape from stock previously rough-formed by casting, forging, rolling, or extrusion. The machining is done with tools having sharp cutting edges made of materials harder than the metal to be cut. There are a variety of machining operations, such as turning, boring, facing, shaping and planning with single-point tools; milling flat or formed surfaces with multipoint milling cutters; originating holes with two-lipped drills; enlarging holes to size with reamers; broaching internal or external surfaces with multitooth broach cutters; and threading, sawing, and grinding, with appropriate tools.
Most metal-machining operations require the use of some type of cutting fluid. Machining of metals causes deformation, rubbing, and friction. The resulting temperature rise can warp the work and damage or excessively wear the tool. Also, the metal will tend to expand, causing inaccuracies in the work. Cutting fluids are used mainly for cooling, but they may serve other purposes. In certain instances the surface finish is improved by the use of a cutting fluid. Often the fluid also serves to lubricate the slides on the machine or to protect the machine from corrosion. In many operations the fluid washes away metal chips and particles that could clog or interfere with the tool and the machine.
Cutting fluids commonly applied to the work and tool to assist in cutting operations include air, used as suction or blast, water containing an alkali; an emulsion of soluble oil and water, straight mineral oils or mixtures of mineral oils with fatty oils, and straight oils or mixed oils that have been sulfurized, chlorinated or both. The sulfurized oils are used for low cutting speeds on operations such as threading, gear cutting, reaming, and broaching primarily to provide good surface finish and high dimensional accuracy. The use of oils increases cutting speeds by 8 to 15%.